The delivery of oil to components requiring lubrication and thereafter scavenging the oil is well known in the art.
A prior art search has revealed the following U.S. patents having some relevancy to scavenging of lubricating oil: Jones Pat. No. 1,958,145; Weeks Pat. No. 2,503,016; Syrovy Pat. No. 3,025,672; Bill et al Pat. No. 3,075,349; Luenberger Pat. No. 3,075,690; Venable Pat. No. 3,378,104; Kievit Pat. No. 3,442,444; DeLisse Pat. No. 3,618,710; and DeSalve Pat. No. 4,285,632.
Generally, the foregoing patents relate to scavenge oil systems without any reference to scavenging oil from a housing which may operate in several different attitudes, by use of a scavenge pump which only pumps oil when required by the attitude of the housing. The Venable Pat. No. 3,378,104 discloses an air-oil separator for use in gas turbine engines and makes reference to operation of the aircraft in a steep climb which would change the attitude of the mechanism. The patent refers to scavenging oil during a steep climb or dive of the aircraft to prevent flooding of the gearbox. However, the solution achieved in this patent is by oversizing a scavenge pump and there is oil in the gearbox at all times that can cause churning losses.
The foregoing prior art does not disclose a scavenge oil system for a mechanism, such as a blower associated with a gearbox, wherein lubricating oil is supplied from the gearbox and the scavenged lubricating oil is returned to the gearbox either by gravity flow to the gearbox or, in certain attitudes of the mechanism, by pumping of the oil by a scavenge pump which is not effective to pump oil in those attitudes where the scavenged oil can flow by gravity to a scavenge pump outlet of the mechanism. When the blower is mounted on top of the gearbox, the flow from the scavenge oil outlet back to the gearbox can be by gravity. If the blower is mounted at the side of the gearbox, the scavenge oil outlet of the blower can be connected by passage means to a scavenge pump within the gearbox.